Boost regulator



C. E. 'CQLE BOOST REGULATOR June 29, 1948.

2 Sheets- Sheet 2 Filed Nov. 15, 1946 -INVENTOR L'HIIHLE5 E. LULEATTORNEY- f,

' Patented June 29, 1948 2,444,185 BOOST REGULATOR Charles E. Cole,Tenafly, N. J., assignor to Bendix Aviation Corporation, Teterboro, N.J., a corporation of Delaware Application November 15, 1946, Serial No.709,923

The present application relates to devices and systems for the controlof alrcraft'engines and to improvements in the regulator disclosed inthe copending application Ser, No. 596,472, filed May 29, 1945, byHoward A. Alexanderson and Robert Z. Hague, and assigned to BendixAviation Corporation.

More particularly the present invention relates to a boost regulatorincluding a hydraulic motor, servo valve and manually operated means forphysically disturbing the servo valve in the event of obstruction orupon the servo valve becoming jammed.

An object of the present invention is to provide a novel releasablevalve actuating element interconnected with the control linkage of theboost control in such a manner that the servo valve may be readilydislodged under manual control upon obstruction to movement of the servovalve.

Another object of the invention is to so arrange the valve actuatingelement as to avoid interference with the operation of the servo valveduring normal operation and in such a manner that the servo valve may bemanually disturbed from a servo increase position only under thecondition of full throttle open position and with the pilot's control ator near full decreased pressure" position.

Another object of the invention is to provide a novel boost controlhaving an operative linkage including a fixed pivot for elfecting manualoperation of the throttle and means for permitting the latter fixedpivotto float in an arcuate path to allow free movement of the throttleunder the automatic operation of a hydraulic motor controlled by a servovalve normally operated by a pressure responsive mechanism, togetherwith a member operatively connected to thefloating pivot and adapted toreleasably engage the servo valve so as to efiect dislodgement of theservo valve when stuck by appropriate manipulation of a pilot's controllever.

Another object of the invention is to provide in combination 'with'thereleasable servo valve engaging member, novel spring tension means forlinking the pressure responsive mechanism to the servo valve so as topermit relative movement I between the valve and pressure responsivemechanism without applying an undue strain to the operative partsthereof.

These and other objects and features of the invention are pointed out inthe following description in terms of the embodiment thereof which isshown in the accompanying drawings. It is to be understood, however,that the draw- 11 Claims. (01. 123-403) 2 ings are for the purpose ofillustration only, and are not designed as a definition of the limits ofthe invention, reference being had to the appended claims for thispurpose.

' In the drawings:

Figure 1' is an exploded schematic view of the boost control of thepresent invention.

Figure 2 is a schematic view of an engine con- .trol system with theboost control in operative relation.

Referring to the drawing of Figure 2, there is shown an aircraft engineI driving a propeller; and a supercharger or blower 3. The super--charger 3 has an air inlet conduit 4 including an air scoop 5 and acarburetor 6 of conventional type. The outlet of the supercharger 3 isconnected to an intake manifold l of the engine I.

A conduit 8 leads to the carburetor 6 from a suitable source of fuel,while a second conduit 9 conducts fuel from the carburetor 6 to asuitable nozzle In. There is also connected to the nozzle In a conductorII which leads from a supply or anti-detonant fluid such as water,water-alcohol or other suitable fluid well known in the art.

There is provided a tank l2 for carrying the anti-detonant fluid. Thetank I2 is connected by a conduit l3 to a fluid pump it which has anoutlet conduit IS. The conduit I 5 leads through an electromagneticallyoperated control valve Hi to a regulating valve ll of conventional typeto the conduit l I.

The control valve I8 is arranged to permit the passage of anti-detonantfluid through the conduit 15 upon energization of its controlelectromagnet. Upon deenergization of the electromagnet controlling thevalve iii the conduit I5 is closed to the passage of the anti-detonantfluid.

A by-pass valve ill in the latter case permits the return of the fluidfrom the conduit E5 to the inlet conduit l3 of the pump l4.

A circuit for energizing the electromagnet for control of the valve i6is indicated generally by the numeral 20 and includes a source ofelectrical energy 2|, a main control switch 22 and a second switch 23carried in an automatic boost control 24 as will be expainedhereinafter.

The automatic boost control 24 operates so as to maintain the pressurein the intake manifold 1, according to the setting of a pilot's controllever 25, by regulating a throttle valve .26 in the conduit 4. Theintake manifold 1 is connected to the automatic boost control 24 througha con duit 21. The pilots control lever 25 is connected to the automaticboost control by a linkage 28 and arm 29, while the throttle valve 26 isoperati'vely adjusted by the automatic boost control 24 through a'link38 and an arm 3| shown in Figure 1.

The mechanism enclosed within the housing of the automaticboost control24, as shown schematically in Figure 1, includes a cam shaft 32; a maincontrol shaft 33 fixedly connected to the arm 29; a throttle controlshaft 34 fixedly connected to the arm 3|; a pressure resppnsive bellowsassembly 35; an operating piston 38; a selector valve 31; a manualcontrol piston 38; and a manual control shaft 39. The motion of thevarious operating linkages is transmitted to, or from,

the four horizontal shafts seated in the unit 24.

Three of these shafts, the main control shaft 33, the cam shaft 32 andthe throttle. control shaft 34 extend along a common axis X--X runningthrough the main cover and the rear wall of the housing of the unit 24.The fourth, the manual control shaft 39, extends along a parallel axisYY above and to one side of the axis X-X.

Cam shaft and cam follower mechanism the driving head of the throttlecontrol shaft 34 in which it turns independently. The other end of theshaft 32 is keyed into the slotted end of the main control shaft 33 towhich the cam shaft 32 is thus drivingly engaged.

A selector cam 4| is mountedupon, and pinned to the cam shaft 32. As thecam shaft 32 is rotated, the cam 4| pivots about the axis X-X andpresents a variable profile to a follower 42 carried by an L-shaped camfollower lever 43. The upper end of the cam follower lever 43 isattached to a spring assembly 44 anchored to a stud 45 in the housing ofthe unit 24. The side arm of the L-shaped cam follower lever 43 swivelson a pivot pin 45 carried by the inner casing of the unit 24. l

The lower portion of the cam follower lever 43 is pivotally connected at41 to a walking beam 48 so that achange in the setting of the cam 4|causes the cam follower lever 43 to swivel accordingly, resulting in acorresponding change in the setting of the walking beam 48. The walkingbeam 48 is coupled at one end to the pressure responsive bellowsassembly 35 and at the other end to the selector'valve 31 as will beexplained hereinafter under the heating Pressure responsive bellowsassembly.

The cam shaft 32 also has a crank arm 50 pinned at the end adjacent tothe throttle control shaft 34. The crank arm 50 is link coupled to themanual control mechanism described below.

Manual control mechanism pinned. The driving lever 54 is freely mountedon the shaft 39 within a slot 55 in the driving head 53, so that as thedriving head 53 swivels downward or is rotated in a clockwise directionby to the driving lever 54 by a set screw 58 in the driving head 53,which bears upon the driving lever 54. The end of the driving lever!" ispin coupled to a push rod 51 which is slidably mounted in a bracket 58.The bracket 58. riveted to the inner wall of the unit 24, guides thepush rod 51 and supports a coil spring 59 against which the push rod 51reacts. The spring 59 biases the push rod 51 in an upward direction andthe driv ing lever 54 in a counterclockwise direction into engagementwith the set screw 55. There is affixed at the lower end of the push rod51 a hooklike actuating element 83 which is arranged to co-. operatewith a pin 5| projecting from the head of the selector valve 31 for apurpose described hereinafter under the heading fSelector valve.

A driving arm 52 is afllxed to the manual control shaft 39 between armsof a manual control piston linkage arm 53 which is freely mounted on theshaft 39. The driving arm 52 is pin coupled at 64 to the center of afloating lever 55. The ends of the floating lever 55 are in turn coupledby links 58 and 61 to the crank arm 58 of cam shaft 32 and a crank arm88 aiflxed to throttle control shaft 34.

Rotation of thecam shaft 32 may be transmitted to the manual controlshaft 39 through the floating lever 55 and driving arm 62. The manualcontrol piston linkage arm 53 is mounted so that it swivels freely uponthe manual control shaft 39. The arm 53 carries an adjustable set screw59 adapted to contact a web portion of the manual control shaft drivingarm 52 and thereby restrain movement of the arm 82 under certainconditions of operation. The swivelling end of the arm 53 is coupled bya pin 18 to a piston rod 1| of the manual control piston 38 biased undertension of a spring 12 in a downward direction and the operation ofwhich is described hereinafter under theheadlng Manual control piston.The manual control mechanism is claimed generically in the copendingapplication Serial No.

596,472, flled May 29, 1945, by Howard A. Alexanderson and Robert Z.Hague, and assigned to Bendix Aviation Corporation.

Throttle control shaft The throttle control shaft 34 is seated in abushing installed in the rear wall of the housin Pressure responsivebellows assembly As previously described, the cam follower lever.

43 is coupled to the walking beam 48 by a pin 41 so that movement of thecam follower lever 43 changes the pivotal position of the walking beam48. The walking beam 48 is coupled at one end to the selector valve 31,and at the other end to the bellows assembly 35.

The bellows assembly consists of a spring-loaded evacuated bellows 15and a pressure bellows 16 which are enclosed between end plates 11 and18 and separated by a center plate 19. The bellows assembly 35 isinstalled in the housing chamber of the unit 24 where it is supported atthe action of the shaft 39, a thrust is transmitted .75 its top by theend plate 18 aiflxed to the inner wall of the unit 24 and at its bottomby a bellows support 80 which likewise afllxes the end plate 11 to theinner wall of the unit 24. The conduit 21 opens into the pressurebellows 16 so that the position of the center plate 19 varies withchanges in intake manifold pressure. An adjustable bellows stop atextends into the pressure bellows chamber 16 and determines the minimumpressure, or lockout setting. The lockout feature is claimed genericallyin copending application Serial No. 550,646, filed August 22, 1944, byHoward A. Alexanderson as a division of application Serial No. 417,855,filed November 4, 1941, and now U. 8. Patent No. 2,358,845, grantedSeptember 26, 1944, and assigned to Bendix Aviation Corporation.

The bellows stop 8| projects above the mounting plate 19 where it may besecured in position by a suitable cap and Jam nut not shown. The bellowssupport'80 may also be in the form of an adjustable post or' screw whichmay be adjusted externally so as to provide a convenient means for varyn the initial pressure setting of the bellows assembly 35.

The bellows 15 is formed of equal size tothe bellows 16 so as tocompensate for changes in atmospheric pressure acting externallyupon-the bellows 16. I

Resilient link assembly The bellows center plate 19 has a connecting arm82 which is connected to the end 01' a resilient link assembly 83. Theassembly 83 includes a tube 84 connected by a link 85 to one end of thewalking beam 48 and a plunger 86 slidably' mounted in the tube 84 andconnected to the arm 82. The plunger 86 is loaded by a coil spring 81which bears at opposite ends on plates 89 and 89 slidably mounted on theplunger 96 and within the tube 85. Theplates 88 and 39 are biased by thespring 81 into engagement with inner portions of the tube 84 so as toprovide a resilient means of relief in case the servo valve 31 is eitherpushed down or pulled up mechanically.

The resilient link assembly 83 is thus arranged so as to preventunnecessary strain from being applied to the bellows assembly 35, asupon the actuating element 80 engaging the pin 6| of the selector valve31 in upward or downward manual adjustment as described hereinafter.This feature is claimed generically in copending application Serial No.783,237, filed October 31, 1947, by Howard A. Alexander'son, as acontinuation of a plication Serial No. 508,724, filed November 2,

the port holes 92 or 93,- thei'eby permitting the flow of pressure oilthrough the bushing orifices the piston 38 as described in the followingparagraph. Drain oil-is passed out through outlet passages 94 or 95.

Operating piston assembly The operating piston assembly 39 travelswithin a housing chamber having a necked opening 96 in its top throughwhich the piston rod extends. Pressure oil to actuate the piston is fedthrough passages 92 or 93 from the selector valve 31. These passageslead to ports opening into the chamber near the upper and lower limitsor travel of the piston 36. Upon adjustment of the valve 31 upward fromthe neutral position, oil pressure is appliedthrough passage 91 andupper port 92 so as to act against the top of the piston'36, forcing itdownward, while the lower port 93 is opened to the oil drain passage 35.Conversely upon adjustment of the valve 31 downward from the, neutralposition oil pressure is applied throughpassage 9| and lower port 93 soas to act against the bot- I tom of the piston 36, forcing it upward,while the upper port 92 is open to the oil drain passage 94.

Motion of the operating piston 36 is transmitted through link 14t'ojarmfifl and thereby to the throttle control shaft 34 so as tocontrol the position of the throttle 26. 7

Manual control piston The manual control piston 38 travels in the upperhalf of a housing chamber 91 from which leads the passage 9| and intowhich housing chamber opens a passage 98 leading from the engine oilpressure supply system or other suitable source of pressure. The manualcontrol piston rod 1| couples the piston 38 to the manual controllinkage assembly through the pin 10 and arm 63. The spring 12 seatedbetween the top of the piston 38 and the top of the chamber 91 in whichit travels, biases the piston 38 in a downward direc- .tion. The manualcontrol piston spring 12 applies extreme position at which the set screw69 con- 1943, and now abandoned, and assigned to Bendix AviationCorporation.

Selector valve The selector valve 31 which is connected to the bellowsassembly 35 through the walking beam the housing of the unit 24. Portholes through the bushing connect a passage 9| leading from a source ofoil pressure to the inlet ports 92 or 93 of the chamber for the piston36. Valve lands at fixed positions along the valve stem 31 cover theport holes 92 and 93 of the bushing when the valve 31 is in a. neutralposition. When the selector valve 31 is actuated through its linkcoupling with bellows walking beam 48 or when it is pushed downward orupward by the thrust of the manual control push rod 51 from the neutralposition, the lands oi. the valve stem 31 uncover the spring I01 in anupward direction and the 'tacts the arm 62 so as to limit free movementof the arm 62 in a'-'counterclockwise direction, while but limitedmovement of the arm 62 in a clockwise direction may be effected due to astop pin 99.

There is further provided at the lower end of the selector valve 31 apiston I90 having a spring I01 and a stem N12. The piston I00 is biasedby stem 102 is arranged to cooperate with the lower end of the selectorvalve 31.

The piston I00 is slidably mounted in a chamber I04 into which opensatthe upper end a passage "15 leading from the passage 9|. Upon theengine oil pressure decreasing below the aforenoted predeterminedminimum value, the spring I01 applies sufllcient force to the piston 100so as to force the stem I02 into contacting relation with the lower endof the selector valve 31 and force the selector valve 31 upward from aneutral position and thereby open' passage 93 to the drain 95 and thepassage 92 to the passage 9|. This permits manual movement'of the piston36, together with the throttle 26 through arm 23, shaft 33, shaft 32,arm 60, link on pin 64, link 31, arm 3|, and link 30.

When oil pressure exceedingthe predetermined 68, throttle shaft 36, arm

63. walking beam 66 pivoted I sure supplied to the unit 24. The lattermanualminimum value of, for example, thirty p. s.- i. is

fed into the chamber 91 through passage 38, the

force of the oil pressure drives the piston 38 upward, thereby movingthe manual control piston linkage arm 63 upward and freeing the manualcontrol shaft driving arm 62 from contact with the set screw 69.Moreover, the latter increased pressure likewise acts upon the piston Iforcing the same into the downward position andwthe stem Hi2 out ofcontacting relation with the selector valve 31 so that normal automaticcontrol of the piston 36 may bmeilected. The manual control pistonarrangement, effective upon oil pressure failure, is claimed genericallyin the copending application Serial No. 596,412, filed May 29, 1945, byHoward A. Alexanderson and Robert Z. Hague, and assigned to BendixAviation Corporation.

M am control shaft' The main control shaft 33 is mounted in a sleevebearing in the cover of the unit 24 in such a position as to engage thekeyed end of the cam shaft 32. Rotation of the shaft 33 is limited by amain control shaft stop pin I06 afllxed to the internal wall of the unit26 and cooperating with a flange I01 afflxed tothe internal end of theshaft 33. The lever 23 is afixed to the external end of the shaft 33 foroperation by the pilot through link 26 and the pilots control lever 25,as shown in Figure 2.

Water injection control The switch 23 for controlling the electriccircuit 20 previously described, may be in the form of a micro-switch orsuitable spring operated snap switch installed in the upper portion ofthe main cover assembly of the unit 25.

The switch 23 is actuated by a push rod I08 operated by a cam I09 amxedto the control shaft 33 and arranged so asto close the electricalcircuit 20 through the switch 23 when the manifold pressure selected bymovement of the lever 29 corresponds to a predetermined value of, forexample, in excess of 52.25 inches Hg absolute (corresponding toapproximately 59 degrees of pilots control lever angle).

Upon closing the 'switch 23 by such adjustment of the pilots controllever 25, operation of the water injection system is effected.

Operation The unit 26 operates during normal automatic control tomaintain the pressure in the intake manifold 1, according to the settingof the pilot's control lever 26. This function is effected by theoperation of the selective mechanism 41-33 and the automatic controlmechanism 35, 68, 31 and A manual control is provided for enginestarting, idling and taxiing. The latter manual conmanual control incase of failure of the oil pres-= control range is sufficient to obtainnormal power for take-off engine speed at sea level. i

The selective mechanism is centered about the cam 4| and its associatedfollower linka e 63. Movement of the pilot's control lever 26 rotatesthe cam shaft 32, through the main shaft 33 to which it is coupled, andcauses the selector cam M to swivel around the shaft axis X-X, therebypresenting a variable profile to the cam follower 43. When the pressuresetting is increased by clockwise movements of the arm 29, the cam Mswivels upward causing the cam follower 43 to pivot about 46 in acounterclockwise direction away from the cam shaft 32. This movement ofthe cam follower 43 causes the walking beam 46, to which it is pincoupled at 41, to swivel about the pivot pin 41 and move the selectorvalve 31 downward in a pressure increasing direction so as to therebyincrease the pressure setting of the bellows assembly 35. Converselymovement of the arm 23 in a counterclockwise direction decreases thepressure setting. a After the selective mecnanlsm has adjusted theposition of the walking beam according to the setting of the pilotscontrol lever, the automatic control mechanism operates to maintain themanifold pressure according to this setting.

described. Above decrease the manifold pressure.

When the pressure at the intake manifold 1 decreases below the selectedsetting, the deflciency is sensed by the pressure bellows 16 whichcontracts accordingly, thereby moving the center plate 19 upward. -Themotion of the center plate 13 is transmitted through the resilient linkassembly' 83 to the walking beam 48 which pivots on the pin 41 into aposition whereby the selector valve 31, at the opposite end of thewalking beam 68, is'thrust downward to a pressure increasing position.In the latterposition of the selector valve 31, the passage 3| is opento the passage 93 leading to the lower end of the operating pistonchamber, and oil pressure is thus applied against the lower face of theoperating piston 36. Simultaneously the upper passage 92 of theoperating piston chamber is opened to the drain passage 34, so that thepiston 36 moves upward in its chamber. This motion is transmittedthrough the piston rod 16 to the throttle shaft 36 which is thusactuated in a clockwise direction to increase the opening of thethrottle valve 26 and thereby increase the pressure at the intakemanifold I. Conversely, when the manifold pressure increases to a valueabove the selected setting, the pressure bellows l6 senses the increasedpressure and causes the operating piston 36 to move upward in adirection which causes the throttle 26 to move in a closing directionand In either case, when the pressure at the intake manifold l isincreased or decreased to the value required by the selective setting,the pressure bellows it reacts to close the selector valve ports 92 and33, thus returning the control mechanism to the stable position until afurther change in flight conditions, or a new setting of the pilotscontrol lever 25, requires a corresponding readjustment of the manifoldpressure.

At pressure settings demanding a value of manifold pressure for whichthe throttle valve 26 would tend to assume a position at less than aprescribed minimum angle, the boost control automatically shifts intothe manual control range. Within the latter low pressure setting rangethe automatic lock-out 61 engages the center plate 18 and preventscontraction of the neutral position at selected pressures below apredetermined minimum value and the bellows assembly 35 in effectcontinuously calls for less pressure.

Thus, upon, adjustment of the cam 4f towithin the low pressure lock-outrange, the piston 35 tends to move downwardly until the throttle valve23 assumes a position approaching the prescribed minimum angle,whereupon the arm 63 is moving in a counterclockwise direction so as toactuate the link 81 downwardly together with the attached end of thefloating lever-35 so as to actuate the manual control shaft driving arm62 in a clockwise direction to transmit motion to the manual controlshaft 39. Such rotation of the shaft 39 pivots the manual controldriving head 53 and lever 54 downward thereby driving the push rod 51downward. At the prescribed minimum angle the push rod 51, in turn,thrusts downward on the raised selector valve 31 returning the same toaneutral position against the tension of the resilient linkage 83.

Further closing movement of the throttle valve 23 is effected as adirect follow-up of movement of the arm 23 in a counterclockwise orpressure decreasing direction. Thus such further movement will cause thearm 50 of the cam shaft 32 to move in a counterclockwise directionraising link 66 and the attached end of the walking beam 35 so as tomove arm 62 in a counterclockwise direction, whereupon spring 59 biasesthe push rod upward so as to release the walking beam 48 under force ofthe tension spring 81 of the resilient linkage 83 to move the valve 31in an upward direction from the neutral position. The latter adjustmentof the valve 31 will in turn cause piston 36 to move downward so as tofurther close the throttle 26 and to return the selector valve 31 to aneutral position through action of the push rod 51, which is then moveddownward by the action of the driving head 53 and lever '54 upon thedownward movement of the piston 36.

In the aforenoted manual range, movement of the arm 29 to increase themanifold pressure rotates the cam shaft arm 50 clockwise. The throttlecontrol shaft 34 is momentarily fixed, and the downward thrust of thecam shaft arm 50 actuates the manual control shaft driving arm 62 in aclockwise direction to transmit the motion to the manual control shaft39. The rotation of this shaft pivots the manual control driving head 53and lever 54 downward thereby driving the push rod 51 downward. The pushrod 51, in turn, thrusts downward upon the selector valve 31, pushing itinto the increase pressure position whereby oil pressure is fed to theoperating piston 36 upward to increase the opening of the throttle 26and simultaneously to actuate'the arm 62 in a counterclockwisedirect-ion so that the selector valve under tension of the resilientlink 83 may be returned to a neutral position.

If the oil pressure supply to the unit is insunicient due to oilpressure supply failure or other cause, the piston 38 under force of thespring 13 actuates the arm 63 in a clockwise direction so as to limitmovement of the driving arm 62. In this case, the pivot 64 is fixed andthe floating lever Bv pivots about an axis which directly moves thethrottle control shaft 34. The pivotal action of the cam shaft arm 50 istransmitted through the linkage system composed of the floating lever 65and the two connecting links 68 and 61, to the throttle shaft 34 whichrotates'accordingly. The

piston 36 may be moved manually due to the action oi. the piston I00 inbiasing the valve 31in an upward direction upon such pressure failure.

During normal operation when the pilots control lever is moved beyond apredetermined angle of, for example, 59 degrees and corresponding,forexample, to a pressure setting of 52.25 inches Hg absolute, theswitch cam I09 mounted on the main control shaft 32 actuates themicroswitch 23 so as to close the circuit 20 and thereby automaticallyturns on the water injection system. A novel feature of the presentinvention is the provision on the push rod 51 of the hook-like actuatingelement 60. The actuating element 60 is so arranged that the valve 31may be readily dislodged thereby should the valve v.31 become jammed orstuck in the downward or pressure increase position and thus renderingthe control unit 24 unresponsive to movements of the pilots controllever to decrease power.

In such case, with the piston at the extreme upward pressure increaseposition and the valve 31Jammed in the downward position, dislodgementof the valve 31 is accomplished by manually moving the pilots controllever 25 to the full pressure decrease position. The latter actioneffects movement of the arm 29 in a counterclockwise direction whichimparts acorresponding counterclockwise movement to the arm moving thelink 66 and floating lever 65 upward so as to in.

of the valve 31 from its downwardly stuck position.

In order to avoid interference with the valve 31 in servo increasepositions during normal autome-tic operation, the valve disturbingelement 30 is inter-connected with the control linkage in such a mannerthat the valve 31 is disturbed from servo increase position only underthe condition of full throttle servo position with the pilot's controlat or near "full decrease" position.

By virtue of the geometry of the particular linkage under consideration,a definite position is determined for the arm 62 for any specificpositions of the throttle control arm 68 and the pilot controlled arm5!]. The valve disturbing element BI] is then mechanically connected tothe arm 62 throughishaft 39, head'53, lever 54, push rod 51 and spring59 and so proportioned as to create an interference tending to displacethe valve 31 in the pressure decrease direction, upon the arm 50 beingat full throttle position and the arm 50 being at or near "full decreaseposition. The force applied to the valve 31 is supplied by the coilspring '59 acting upon the valve. disturbing element 50 through the pushrod 51. It will be seen that theresllient linkage 83 permits movement ofthe servo valve 31 relative .to the pressure responsive mechanism 35without applying an undue strain on the mechanism.

Although only one embodiment of the invention has been illustrated anddescribed, various changes in the form and relative arrangements of theparts, which will now appear to those skilled in the art, may be madewithout departing from the scope of the invention. Reference is, there--fore, to be had to the appended claims for a deflnition of the limits ofthe invention.

What is claimed is:

1. For use with a supercharged aircraft engine having an air intakemanifold and a throttle valve for controlling the induction pressure; aboost regulator including hydraulic power means for controlling thethrottle valve, a servo valve for controlling the power means, apressure sensitive device for actuating said servo valve upon changes inthe induction pressure, means for changing the datum of said boostregulator, means for operating said datum changing means, releasablemeans for dislodging said servo valve when stuck in an inductionpressure increase position, and means operably connecting saiddislodging means to said operating means.

2. For use with a supercharged aircraft engine having an air intakemanifold and a throttle valve for controlling the induction pressure; a

I boost regulator including hydraulic power means for controlling thethrottle valve, a servo valve for controlling the power means, apressure sensitive device for actuating said servo valve upon changes.in the induction pressure, means for changing the datum of said boostregulator, means for operating said datum changing means. releasablemeans for dislodging said servo valve when stuck in an inductionpressure increase position, and means operably connecting saiddislodging means tosaid operating means in such a manner as to eflectactuation 01' said dislodging means only within a predetermined limitedrange of adjustment or said operating means,

3. For use with a supercharged aircraft engine having an air intakemanifold and a throttle valve for controlling the induction pressure; aboost regulator including hydraulic power means for controlling thethrottle valve, a servo valve for controlling the power means, apressure sensitive device for actuating said servo valve upon changes inthe induction pressure, means for changing the datum of said boostregulator, means for operating said datum changing means, releasablemeans for dislodging said servo valve when stuck in an inductionpressure increase position, and means operably connecting saiddislodging means to said operating means and said power means in such amanner as to effect actuation of said dislodging means only when saidhydraulic power means has been adjusted to a substantially maximuminduction pressure position and said operating means has been adjustedto a substantially extreme induction pressure decrease position.

4. The combination with an internal combustion engine having an intakeconduit and a throttle valve for controlling flow of combustible mixtureto said intake conduit, automatic means responsive to engine intakepressure and including a servo valve and hydraulic motor means forpositioning said throttle valve, manual means operabl while the engineis running for setting the automatic means for the desired intakepressure, releasable means for dislodging said servo valve when stuckin'an intake pressure increase position, and means operably connectingsaid dislodglng means to said manual means.

5. The combination with an internal combustion engine having an intakeconduit and a throttle valve for controlling flow of combustible mixtureto said intake conduit, automatic means responsive to engine intakepressure and including a servo valve and hydraulic motor means forpositioning said throttle valve, manual means operable while the engineis running for settin the automatic means for the desired intakepressure, releasable means for dislodging said servo valve when stuck inan intake pressure increase position, and means operably connecting saiddislodging means to said manual means in such a manner as to effectactuation of said dislodging means only within a predetermined limitedrange of adjustment of said manual means.

6, The combination with an internal combustion engine having an intakeconduit and a throttle valve for controlling flow oi combustible mixtureto said intake conduit, automatic means responsive to engine intakepressure and including a servo valve and hydraulic motor means forpositioning said throttle valve, manual means operable while the engineis running for settin the automatic means for the desired intakepressure, releasable means for dislodging said servo valve when stuck inan intake pressure increase position, and means operably connecting saiddislodging means to said manual means, and said motor means in such amanner as to efiect actuation of said dislodging means only when saidhydraulic power means has adjusted said throttle valve to substantiallya maximum intake pressure position and said manual means has beenadjusted to substantially an extreme intake pressure decrease position.

'7. A boost regulator comprising a hydraulic power means, a valve forcontrolling the power means, a pressure sensitive device ioractuatinsaid valve, a releasable element for engaging said valve, spring meansfor actuating. said element into engagement with said valve so as toactuate said valve in one sense, manually operable means. means forcontrolling said spring actuating means, and means operably connectingthe control means to said power means and said manually operable means.

8. A boost regulator comprising a hydraulic power means, a valve for.controlling the power means, a releasable element for engaging saidvalve, spring means for actuating'said element into engagement with saidvalve so as to actuate the value in one sense, manually operable means,means for controlling said spring actuating means, and means operablyconnecting the control means to said power means and said manuallyoperable means.

9. A boost regulator comprising a hydraulic power means, a valve forcontrolling the power means, a releasable element to engage said valve,spring means to actuate said valve through said element, manuallyoperable means, an arm for controlling said spring actuating means, awalking beam pivotally connected intermediate its opposite ends to saidcontrol arm, means operably connecting said power means and saidmanually operable means to opposite ends of said walking beam so as toeffect saidcontrol arm in accordance therewith.

10. A boost regulator comprising a hydraulic power means, a valve forcontrolling the power means, a hook-like element to engage said valve,spring means to actuate said valve through said element, manuallyoperable means, an arm for controlling said spring actuating means, awalking beam pivotally connected intermediate its opposite ends to saidcontrol arm, means operably connecting said power means and saidmanually operable meansto opposite ends of said walking beam so as toeflect said control arm in accordance therewith.

11. For use with a supercharged aircraft engine having an air intakemanifold and a throttle valve for controlling the induction pressure ofsaid engine; a boost regulator including hydraulic power means forregulating the throttle valve. a servo valve for controlling the powermeans, a pressure sensitive device for actuating said servo valve uponchanges in induction pressure, means for changing the datum of saidboost regulator, means for operating said datum changin; means, a pinprojecting from one end of said servo valve, a hook-like element toengage said pin for dislodging said servo valve when stuck in aninduction pressure increase position, spring means to actuate saidelement to effect such distially extreme induction pressure decreaseposition.

CHARLES E. COLE.

Certificate of Correction Patent No. 2,444,185. V I June 29, 1948.

7 CHARLES E. COLE It is hereby certified that error appears in theprinted specification of the above numbered patent requlrmg correctlonas follows: Column 12, km 47, 01mm 8, for the word value read valve; andthat the said Letters Patent should be read with this Signed and sealedthis 28th day of September, A. D. 1948.

THOMAS F. MURPHY,

Assistant Uommz'ssz'oner of Patents.

